A problem inherent in a conventional assembly machine is that operational mechanisms giving an operation to parts are necessary for every assembly station thereby making the assembly machine complex. This fact is reflected in the shortcomings that production costs rise and further that adjustment at a maintenance inspection time is difficult to carry out.
There is also another type of conventional assembly machine where a tool plate is commonly used to provide rise and fall motion (elevator motion) for every assembly station. This type of assembly machine is used only for elevator motion such as for inspection of the existence of the parts on the pallet, and it is not possible to apply it to a transfer operation of the parts.